Circuit breaker



Nov. 3,1936. w- H. FRANK ET A1.

C IRCUI T BREAKER Original Filed Jan. 3,. 1935 INVENTORS /f/d MMUJ, if

Patented Nov. 3, 1936 UNITED STATE cracm'r nimma William H. Frank andJoseph Messing, Detroit, Mich., assignors to Bulldog Electric ProductsCompany, Detroit, Mich., a corporation of West Virginia Originalapplication January 3, 1933, Serial No. l ,649,983,lk now Patent No.1,982,289, November Divided and this application October 26, 1934,Serial No. 750,161

6 Claims. (Cl. 20o-121) This application discloses a circuit breakerunit and is a division of our copending application Serial No. 649,988,filed January 3, 1933, now Patent No. 1,982,289 of November 27, 1934,class 200, sub-class 116.

One principal object is to provide, in connection with circuit breakers,means for indicating the condition of the breaker and/or condition ofthe circuit controlled thereby. More specifically, it is aimed toprovide novel constructions and combinations including heads .forenclosing the circuit breaker proper equipped with indicating devicessuch as lamps, etc., which may be lit upon changes in the condition ofthe breaker and/or the controlled circuit.

. It is contemplated at the present time to provide for a standard formof circuit breaker, interchangeable and convertible heads which may bemade from a single blank, the blank being con-` vertible, as desired,into a simple, breaker-enclosing head, or into a head which not onlyencloses the breaker parts but which also can be equipped withindicating parts.

In one design, theindicating parts will give one indication when thebreaker has been released on overload and will give a differentindication under different conditions. `In a. second design,` theindicating parts will produce three different indications, one, for anoverload release produced by a short circuit, another, for an overloadrelease produced by a relatively light overload, and a third, for otherconditionsof the circuit. This type of indicating means is particularlydesirable In that it not only indicates the existence of an abnormalcondition in the circuit but it also indicates the nature of theabnormal condition. It is contemplated to have the indicating means inthe form of a lamp or`tube so connected that it will be dark when thebreaker is closed, and glow when it is open, as contra-distinguishedfrom prior artfconstructions, wherein the lamp or tube is so connectedthat it will be dark when the breaker is open and glow when it isclosed. l

Further, in the last mentioned design, the indicating means may besotconstructed thatl though the indications on overloads are different,depending upon the nature of the overload, they are both so differentfrom the indication produced by a normal condition of the circuit, thatthough they may readily be distinguished from each other, they may alsobe distinguished from the normal load indication. In a preferredembodiment, following this idea, where the indicating means isin thenature of a neon tube, the design is such that the neon tube will burnbrightly on short circuit, dimly on light overload, and not at all onnormal load.

Further, the indicating means of the last mentioned design permits theoperator to tell at a glance whether it is safe to' close the breaker,

once it has tripped. For example, if the lamp burns brightly as on ashort circuit overload, the operator will immediately know that itisdangerous to close the breaker. However, if the lamp is burning dimly,as on light overload, the operator will know that it is safe to closethe breaker.

A further object is to provide an indicating means wherein a neon tubeis employed as the indicating element, this type of indicator permittingnovel connections, ufor results outlined in the foregoing. i i

Still further objects will be readily apparent to those skilled in theart upon reference to the following detailed description of embodimentsof y Y circuit breakers, the same to be read in connection vwith theappended drawing. Referring to this drawing, it will be seen thatFigures 1 and 2 are cut away elevation views of a circuit breakerprovided with an indicating "means, the breaker being shown in On andoverload OE positions, respectively.

Figures 2a, 2b and 2c show schematically the device of Figures 1 and 2,and two variations thereof.

Circuit indicating means |43, aflexible jumper |43a,a thermal warpingelement T4, and a jumper |43b. Arm |43 jis journalled at`l44, to frame|45, and may be moved by links HIL-|48, connected by an axle pin |49,links |48 being connected by pin |50 to a member 5| journalled in frame|45 at |52.

Pin |44 also journals the operating arm |53 to the upper end of which issecured the arcuate piece |55 formed with a handle |56 by means of whichthe arm |53 can be moved manually, an upper part |58 of arm |53 isconnected by coil springs |59 to pin .|49 and these springs form theoperating springs of the device.

For holding the pin |49 down, on normal loads, there is provided a pawl|60, journalled at I6! and restrained by the warping element T4. It willbe understood that on overload, the latter warps to the right, releasingpawl |60, which in turn releases pin |49, permitting it to be pulledupwardly, and to the left by springs |59.

It will also be understood that when handle |55 is moved to the right,for switch Oli position, pin |49 is moved to the'right and upwardly, butdoes not move to the left.

'I'he construction thus far described is no part of the presentinvention, except insofar as-lt relates to the circuit indicating meansprovided for the device and now about to be described.

For covering those parts of the breaker proper left exposed by the opentop of the base |40, there Yeo ves

may be provided one of two interchangeable and convertible heads, one ofwhich may be equipped with circuit indicating means, (the head shown),and the other of which may be nothing more than a closure.

Both of the heads are substantially alike, differing only in details,and are made from a blank in the form of an insulating cupped block |88provided with end bosses |8| in which are tapped bushings (not shown); acentral cut out |82 in which moves the arcuate piece |55 and the handle|56; a boss |83 provided with a bore |84, closed by a "knockout, (notshown), but positioned at the upper end of bore |84; and a knockout",(not shown), normally closing the opening at |84a.

When the blank is not lto be equipped with circuit indicating elements,the knockouts `are left in place, and the blank forms a head that iscompletely closed, exceptfor cut out |82.

When the blank is to be equipped with the circuit indicatingelements,the knockouts" at bore |84 and opening |84a. are removed and a tell talelamp |85 is positioned and sealed in bore |84, being visible through theopening left by the removed knockout". One lead of the lamp is connectedto a screw |88 in yboss |8| by a flexible lead |81, and the other leadisconnected to a screw |88 in boss |83, as shown.

In the boss |8| near boss |83, there is mounted a screw |89 which clampsin place two resilient contact leaves |90 and |9|, the former of whichhas a forked end straddling the sides of the operating arm |53 and theother` parts of the breaker, the tines of the forked end havinginsulation pieces |92 overlying the extended ends of the linkage pin|49, and positioned to be engaged thereby.

The spring leaf |9| is bent to engage and make electrical contact withthe jumper |4|a of the breaker. l

A conductor Aend |93 passed through opening |84a is held in place byscrew |88 and `connects the lead |81 to that side of the line oppositefrom the line connected to the'jumperl |4|a.

It will be observed at this time that spring leaf |90 is so temperedthat it normally is spaced Vfrom The head may be fitted onto abreaker-equipped base, with its leaf 90 strad'dling the breaker parts,-and with its leaf |9| engaging jumper |4Ia, 'this being accomplishedwithout alteration of the base Under normal load conditions, not engagethe ends |92 ordeal' I or the breaker. thepin |49 will |90 anduwill notmove the latter towards screw |88, thisbeing true even as the pin |49 ismoved to and from its On" and Oil positions.

When an overload occurs, however; pin |49 will move upwardly andto theleft and will engage ends |92 of leaf |90,v moving the latter upwardlyso that it will engage screw head |88. Lamp |85 will thus be placed incircuit with the line conductors and will light, indicating that thecircuit breaker has been released on overload.

It will be observed that the lamp is not in series with the breaker-loadcircuit, but is in multiple therewith, and is mechanically, rather thanelectrically, connected to the breaker.

In Figure 2a., which shows the device of Figures 1-2 schematically, itwill be seen that the circuit through lamp |85 is closed when thebreaker trips, as an overload, due to the engagement of pin |49 and leaf|90. At all other times the lamp circuit is open and the lamp does notlight.

Diierent visual indicating arrangements are contemplated, as alternativeuses of the devices and mechanisms disclosed in Figures 1 2, and theseare schematically indicated in Figures 2b and 2c.

In Figure 2b, the lamp 380 is shown as of the vneon tube type and it isshown as connected in series with the load linev through the medium of aspring contact 30 secured to boss |8| by screw |86 and adapted to engagejumper |43b when the head is placed on the base. Otherwise, the partsare like those shown in Figure 2a. It will be seen that the lamp circuitis closed only when the breaker is tripped by an overload or shortcircuit, the lamp circuitV in this case including the load device whoseshort circuit caused breaker trip.

In Figure 2c, the lamp 300 is also shown as of the neon tube type and itis also shown as connected in series with the load line through acontact 30|, etc. The leaf 3|0, however, is bent downwardly as shown, tobe engaged by contact arm |43, rather than by pin |49, and is insulatedfrom arm |43. Accordingly, the lamp circuit is closed when the breakeris opened,v whether by a normal switch opening operation, or by anabnormal short circuit condition.

From the foregoing, it can be seen that it is possible to obtain a novelvisual indicating effect from the device. For example, assume the lampto be so designed as to burn brightly when in series with an extremelylow resistance (short circuit), to burn dimly when in series with a reisistance of medium strength (light overload) and not to burn -at allwhen in series with a high resistance (normal load), or an infinitelygreat resistance (open. circuit). Under such conditions the lamp willburn brightly on switch opening due to a short'circuit; will burn dimlyon switch opening due to a light overload, and will not burn at all onnormal switch opening. A glance at a lighted lamp will therefore revealnot only the `fact that the breaker has tripped, but also the cause ofthe breaker trip. that' is to say, will reveal not only that the breakerhas tripped, but will also reveal whether a. short circuit (bright) or alight overload (dim) caused the breaker to trip.

Further, a construction of this character may be used to indicate to theoperator whether or not it issafe to close the breaker after trip. 1fthe breaker has tripped, but the lamp is out, the

'operator will know that the circuit back of the breaker was openedafter the event that caused trip, and that it is safe to close thebreaker. Also, if the breaker has tripped, and thelamp is burning dimly,the operator will know that the circuit contains a light'loverload, andthatvthe breaker may be closed safely. But if the breaker has tripped,and the lamp is burning brightly, the operator will know that the'circuit contains a short circuit or a heavy overload and that it wouldbe unsafe to close the breaker.

. In further explanation of the foregoing, the

following discusion as to the characteristics of neon tubes ,will begiven. The successful operation of a neon tube or lamp requires that are sistance be interposed in series therewith. Now, by varying theinterposed series resistance, the sensitivity and lightingcharacteristics of the lamp can be varied to a considerable extent. Forexample, the lamp can be designed to operate in the manner describedabove by determining properly the interposed resistance. y

Further, vwhere the range between the load circuit resistance on shortcircuit and the load circuit resistance on light overhead, etc., for theabove described operation is not great, it is mcontemplated to use, inconjunction with the neon tube, a well known bridge .type circuit, inwhich case the tube would indicate, by its different lightings, not thedifferences in the load circuit `resistances, but the diiference inratios of the load circuit resistances. This arrangement offers anextreme sensitivity to the indicating neon tube.

Further, while it is preferred to use as the indicating means, a neontube, which offers the advantages of low cost, long life, and lowcurrent consumption, it is possible to use ordinary incandescent lamps,with relatively satisfactory results.

It is further contemplated to combine the neon tube with rthe breaker insuch a way that one of the terminals of the tube is connected to thelive conductor on the live side Vof the breaker. In such'a" combination,the neon tube will glow dimly in the event that the breaker is open, orin the event that there is an open circuit on the load side of thebreaker, and the neon tube will burn brightly in the event of -a shortcircuit or heavy overload. The difference in glowings of the tube' willindicate the nature of the circuit line back of the breaker, as can beobserved.

'It will also be seen that in the vconstructions shown, the tube or lampis dark when the circuit is closed or live, and glows when the loadcircuit is open or dead, as contra-distinguished from constructions ofthe prior art, wherein the lamp is connected across the breaker so as tobe dark when the load circuit is open or dead, and glow when the loadcircuit is closed or live. In the last mentioned type of construction,an operator, seeing the lamp dark, will rely upon it as an indicationthat the circuit is open or dead.

This may, however, be a misreliance, since the lamp may be dark, due tothe lamp having been burnt out or become disconnected, even though thecircuit be alive, and this misreliance may lead to serious injury. Inour construction, however, an operator, seeing the lamp dark, willbelieve the circuit to be closed or alive, and will act accordingly.Thus, even if the lamp be dark be' cause of lamp failure, etc., ratherthan because of the circuit being alive, the operator, though he bemisled as to the cause, will not be misled to his injury. I-Ie willdetermine the cause of the lamps being dark and, having satisfiedhimself, may then proceed to work on the circuit.

Now, having described embodiments of circuit breakers, selected by wayof example, reference will be had to the appended drawing whichdetermines the scope of the monopoly desired, it being understood that,except as set out in the claims, the monopoly is not to be limited tothe embodiments disclosed.

We claim:

1. A combined switch and circuit breaker device of the operating typemanually operable for normal switching and operating automatically foroverload release, the breaker having a line shunting the breakercontrolledl line and containing an auxiliary switch and an indicatorenergizable by the breaker controlled line energy when the auxiliaryswitch is closed, the auxiliary switch being constructed and arranged tobe open normally and during manual switching operation and beingconstructed and arranged to be closed automatically by and upon releaseoperation of the breaker and only then to energize the indicator.

2. A combinedv switch and circuit breaker denvice of the operating typemanually operable for normal switching and operating automatically foroverload release, the breaker having aline shunting the breakercontrolled line and containing an auxiliary switch and an indicatorenergizable by the breaker controlled line energy when the auxiliaryswitch is closed, the auxiliary switch being constructed and arranged tobe open normally and during manual switching operation and beingconstructed and arranged to be closed automatically by and upon releaseoperation of the breaker and only then to energize the indicator, theshunt line, the switch, and the indicator being formed as part of aremovable cover of the device.

3. The combined switch and circuit breaker device of the operating typemanually operable for normal switching and operating automatically foroverload release, the breaker havingan indicator energizable by thebreaker controlled line energy, the indicator being constructed andarranged to be deenergized .normally and during manual switchingoperation and being constructed and arranged to be energizedautomatically by and upon release operation of the breaker and onlythen.

4. A construction of the character described in claim 3 wherein theindicator is formed as part of a removable cover of the device.

5. A combined switch and circuit breaker device of the operating typemanually operable for normal switching and operating automatically foroverload release, the breaker havinga line shunting the breakercontrolled line and containing an auxiliary switch andan indicatorenergizable by the breaker controlled line energy when theiauxiliaryswitch is closed, the auxiliary switch being constructed and arranged tobe open normally and during manual switching operation and beingconstructed and arranged to be closed automatically by and upon releaseloperation of the breaker and only then to energize the indicator, thelatter being arranged to give a different iindication when energized bybreaker release following moderate overload from what it gives whenenergized by breakerrelease following excessive overload.

6. A combined switch and circuit breaker device of the operating typemanually operable for normal switching and operating automatically foroverload release, the breaker having an indicator energizable by thebreaker controlled line energy, thev indicator being constructed andarranged to be deenergized normally and during manual switchingoperation and being constructed and arranged to be energizedautomatically by and upon release operation of the breaker and onlythen, the latter being arranged to give a different indication whenenergized by breaker release following moderate overload from what itgives when energized by breaker release following excessive overload. Y

WILLIAM H. FRANK. JOSEPH MESSING.

